Raeann left home at 10.45 a.m. and drove towards the city. 3 hours later, her younger brother left their home and drove towards the same city at 88 km/h. When the younger brother reached the city at 6.45 p.m., Raeann had another 2 km to travel. What was Raeann’s average speed? Express your answer in mixed number.
Time that the Raeann's younger brother started driving = 1.45 p.m.
Duration that Raeann's younger brother drove from 1.45 p.m. to 6.45 p.m. = 5 h

Distance that Raeann's younger brother travelled
= 5 x 88
= 440 km

Distance that Raeann travelled by the time her younger brother reached the city
= 440 - 2
= 438 km

Time that Raeann took to travel 438 km = 8 h

Raeann's average speed
= 438 ÷ 8
= 54³₄ km/h

Answer(s): 54³₄ km/h